A navigation system performs travel guidance for enabling a user to easily and quickly reach the selected destination. A typical example is a vehicle navigation system where a vehicle is equipped with a navigation function to guide a driver to a destination through a calculated route. Such a navigation system detects the position of the user's vehicle, and reads out map data pertaining to an area at the current vehicle position from a data storage medium. Typically, the navigation system displays a map image on a monitor screen while superimposing thereon a mark representing the current vehicle position. At an intersection associated with the calculated route, the navigation system notifies the user which direction to turn at the intersection to reach the destination.
FIGS. 1A-1H show an example of overall procedure and screen displays involved in the operation of the navigation system. FIG. 1A shows an example of locator map screen of the navigation system when the destination is not specified. Typically, the navigation system displays a street on which the vehicle (vehicle position VP) is running on a map image and a name of the street. Other information such as a north pointer NP, a map scale and a current time may also be illustrated on the display screen.
An example of process for specifying a destination in the navigation system through a Point of Interest (POI) search method is shown in FIGS. 1B-1F. A main menu screen such as shown in FIG. 1B displays menu items including a “Destination” menu for entering the destination. When selecting “Destination”, the navigation system displays a “Find Destination by” screen as shown in FIG. 1C for specifying an input method for selecting the destination. The “Find Destination By” screen lists various methods for selecting the destination including “Address” for specifying the city and address of the destination, “Intersection” for specifying the names of two streets which intersect with one another, and “Point of Interest (POI)” for selecting the programmed destination based on the name, category or telephone number.
When selecting, the “Point of Interest” method in FIG. 1C, the navigation system displays selection methods of point of interest (POI) either by “Place Name” or “Place Type” in FIG. 1D. The “Place Name” is to specify a name of POI, and the “Place Type” is to specify a category of POI. If the “Place Type” is selected in FIG. 1D, the navigation system lists categories of POIs as shown in FIG. 1E. The user selects a desired category of destination from the lists.
FIG. 1F shows a screen when the user has selected a “Fast Foods” category in the example of FIG. 1E. In this example, the screen includes the name of POI type “Fast Foods” at the top and a list of names of the fast food restaurants typically sorted by distance from the current position. The user selects a particular restaurant among the restaurant lists for route guidance. In FIG. 1G, the navigation system determines an appropriate route to the destination. After determining the calculated route, the navigation system starts the route guidance as shown in FIG. 1H.
Typically, the navigation system will show an arrival screen such as shown in FIGS. 2A and 2B when the vehicle approaches the destination. The current vehicle position indicator 71 and the destination icon 91 are shown on the map image. The screens shown in FIGS. 2A and 2B are similar to those ordinarily displayed while the navigation system guides the user to the destination, except that the screens show the destination icon 91 that indicates the location of the destination on the map image.
FIG. 2A shows the situation where the user is close to the destination but has not yet fully reached the destination while FIG. 2B shows the situation where the vehicle has reached the destination. In FIG. 2B, the navigation system announces that the vehicle has arrived at the destination when the vehicle is within an arrival detection range such as 300 feet. However, since the destination icon 91 on the map image does not show the accurate location, when there are many houses or buildings within the arrival detection range, the user has a difficulty in estimating the distance to the destination if it is a new place for the user.
Thus, there is a need for a navigation system to allow the user to more easily and accurately estimate the distance from the current use's position to the destination. Japanese Patent Application Laid-Open No. H8-14930 discloses a navigation system including address map database, road map information and a means for detecting current position to synthesize and display them on a screen. According to the navigation system, since many addresses together with town names and the current position are displayed on the road map on a screen, still it is difficult to estimate the distance to the destination when comparing the information obtained from the navigation system with an actual outside view. Further, this prior art discloses an auxiliary display in a route guidance unit for a car in which road guidance information can be confirmed by a left and right turn LEDs, a straight advance indicator LED, a seven-segment LED indicating the number of intersections encountered before turning left or right and LED indicating approach or arrival at a destination. However, since the information obtained from the guidance indicator is to give the user a direction to the destination, it is difficult to estimate the distance from the current position to the destination.